Research links turtle deaths to dredging in harbour

by dburdon

Daniel BurdonDaniel Burdon is APN Australian Regional Media's Canberra bureau reporter, covering federal parliament and politics. He was previously a rural and general news reporter at the Morning Bulletin in Rockhampton and worked in Alice Springs for the Centralian Advocate.

A MAJOR dredging project in Gladstone harbour may have been linked to a spate of turtle deaths in the area, new research by James Cook University has claimed.

The research looked at links between turtle health and marine water quality across the Great Barrier Reef, and contradicts previous State Government reports that largely blamed a flood for the problems.

Led by JCU water quality expert Dr Jon Brodie, the report said a dredging project underway in the harbour in 2011-12 may have exacerbated turtle health problems.

The report found that turtle strandings and deaths across the reef in recent years were suspected to be the result of a "herpes virus" in association with a secondary factor, "the isolation of which remains elusive".

While the 2010 flood was a possible link in the Gladstone harbour strandings and deaths, having reduced seagrass cover, it was also "likely that the elevated metals found in stranded turtles resulted from metals mobilised through dredging".

The report also said the "leakage" of dredging sediment from a bund wall built to hold the spoil may have further added to stress the turtles were under.

The failure of that bund wall is currently being investigated by a review ordered by the Federal Government, tasked with finding out if there were any unacceptable failures in the bund wall structure.

Dr Brodie's research cited a previous study into metals in the blood of 56 turtles that were stranded or died at the time, finding it was likely "that the large scale dredging in Gladstone Harbour may be associated with these elevated metals".

While the Gladstone Ports Corporation, which undertook the dredging, has consistently claimed the turtle strandings and deaths were not associated with the dredging, the JCU study joins a growing number of counter-claims.

The Australian Institute of Marine Science has previously noted all the specific causes of a fish disease outbreak in the harbour may remain "unknown".

However, reports last week confirmed at least one noted chemical in the harbour was overlooked during state and federal government investigations into the 2011 outbreak.